This invention relates in general to the lubrication of automotive parts and deals more particularly with a tool which facilitates lubrication of two-piece drive shafts having splined sliding yokes.
In vehicular drive lines having two-piece drive shafts, a sliding yoke is driven by a shaft which is connected with the yoke by a spline connection which establishes a slip joint between the shaft and yoke. Lubrication of the spline area at regular intervals is necessary in order to prevent undue wear on the slip joint and to force out accumulated dirt, moisture, dried grease and other foreign matter that can contribute to wear on the parts and destruction of the slip joint seal. It is important during lubrication service to completely fill the slip joint with lubricant so that virtually all of the dirt and moisture will be dislodged from the spline area. If significant amounts of dirt and moisture remain, they can significantly reduce the useful life of the splines and yoke and can cause early failure of the seal. Once the seal fails, dirt and other foreign materials are able to enter the slip joint without obstruction and the parts are then rapidly worn.
The sleeve body of the sliding yoke has a grease fitting which permits lubricant to be applied to the slip joint, usually with a hand operated grease gun but sometimes with powered applicators. The yoke end of the sleeve has a vent hole which accomxodates sliding of the yoke, and the vent hole must be covered if the slip joint is to be completely filled with lubricant. If the vent hole is not covered, lubricant can leak through it and the slip joint will not be completely filled. At present, lubrication service normally involves covering the vent hole with the finger while lubricant is being applied, and this practice suffers from a number of problems.
First, the proper operation of the grease gun requires both hands, and the need to cover the vent hole with the finger of one hand leaves only one hand available to operate the grease gun. This leads to awkward situations and poor control of the grease gun. It is also difficult to keep the vent hole constantly covered during the entire lubrication procedure so that a complete filling of the slip joint is assured. If the vent hole is covered with too much finger pressure, the grease gun can apply excessive pressure which can blow out the seal or otherwise damage it. These problems are compounded by the location of the yoke in the cluttered undercarriage area of the vehicle which at best is difficult to reach.
The present invention provides a tool which can be applied to the sliding yoke and which serves to temporarily plug the vent hole while lubricant is being applied to the slip joint. The tool thus frees both hands for operation of the grease gun and permits the spline area to be completely filled with lubricant without significant leakage through the vent hole.
It is an important object of the invention to provide a tool which effectively plugs the vent hole during lubrication and yet automatically relieves excessive pressure applied by the grease gun. As a result, the slip joint seal is protected against being blown out due to excessive grease gun pressure.
Another object of the invention is to provide a tool which is adjustable so that it can be applied to virtually all sliding yokes having vent holes. The adjustability of the tool also permits it to be tightened firmly on the yoke in order to securely maintain it in place during the appliqation of lubricant.
A further object of the invention is to provide a tool of the character described which is small enough to be used in cluttered undercarriage areas and which can be quickly and easily applied to and detached from the sliding yoke.
An additional object of the invention is to provide a tool of the character described which is simple and economical to construct and easy to use.
Other and further objects of the invention, together with the features of novelty appurtenant thereto, will appear in the course of the following description.